CVE-2011-5325 in tar
Summary
by MITRE
Directory traversal vulnerability in the BusyBox implementation of tar before 1.22.0 v5 allows remote attackers to point to files outside the current working directory via a symlink.
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Analysis
by VulDB Data Team • 03/04/2025
The vulnerability identified as CVE-2011-5325 represents a critical directory traversal flaw within the BusyBox tar utility implementation that affected versions prior to 1.22.0. This weakness specifically manifests when processing symbolic links during tar archive extraction operations, creating a pathway for remote attackers to access files outside the intended extraction directory. The flaw resides in how the tar command handles symbolic link resolution, particularly when these links point to locations outside the current working directory, enabling unauthorized file access and potential data exposure. This vulnerability is particularly concerning in networked environments where tar archives may be processed from untrusted sources, as it can be exploited to read arbitrary files on the system.
The technical implementation of this vulnerability stems from insufficient validation of symbolic link targets during tar archive extraction processes. When tar encounters a symbolic link within an archive, it should properly validate that the target remains within the designated extraction boundaries. However, the BusyBox implementation failed to adequately enforce these boundaries, allowing maliciously crafted archives to contain symbolic links that point to sensitive system files outside the intended extraction scope. This behavior directly violates the principle of least privilege and can be exploited to bypass normal file system access controls. The vulnerability specifically affects systems running BusyBox versions before 1.22.0, making it a version-specific issue that required targeted patching efforts across affected deployments.
The operational impact of CVE-2011-5325 extends beyond simple file access violations to encompass broader security implications for system integrity and data confidentiality. Attackers can leverage this vulnerability to read sensitive files such as configuration data, authentication credentials, or system binaries that should remain protected from unauthorized access. In environments where tar archives are processed automatically or from untrusted sources, this vulnerability can lead to complete system compromise through information disclosure. The attack vector is particularly dangerous in web environments where users might upload tar archives that are then automatically extracted by server processes, potentially allowing remote attackers to access critical system files. This vulnerability aligns with CWE-22 Directory Traversal and can be mapped to ATT&CK technique T1059.007 for execution through archive extraction processes.
Organizations affected by this vulnerability should prioritize immediate patching of all systems running BusyBox versions prior to 1.22.0 to prevent exploitation. The mitigation strategy involves upgrading to BusyBox 1.22.0 or later, which includes proper symbolic link validation during tar operations. Additional protective measures include implementing strict file access controls, monitoring archive extraction activities, and restricting the execution of tar commands from untrusted sources. Network segmentation and access control lists can help limit the potential impact of exploitation attempts, while regular security audits should verify that no systems remain vulnerable. The vulnerability serves as a reminder of the importance of proper input validation in system utilities and the critical need for maintaining up-to-date security patches across all system components.